In-order fibre channel packet delivery

• US 7,649,844 B2
• Filed: 12/29/2004
• Issued: 01/19/2010
• Est. Priority Date: 12/29/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bector, Rajeev, Jain, Sachin, Mahajan, Umesh, Mellacheruvu, Ramana
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): Samuel; Dewanda
• Application Number:
  US11/027,252
• Publication Number:
  US 20060153186A1
• Time in Patent Office: 1,847 Days
• Field of Search: 370/431, 370/412, 370/389, 370/228, 370/235, 370/231, 370/244, 370/248, 709/232, 709/238
• US Class Current: 370/235
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/3045 Virtual queuing
• CPC Class Codes: H04L 49/357 Fibre channel switches

Abstract

Methods and apparatus are provided for improving fiber channel packet delivery. Techniques are provided for the in-order delivery of packets by blocking incoming packets associated with a port channel change at a fiber channel switch and sending flush messages onto links associated with a port channel change. Upon receiving acknowledgments for the flush messages, incoming packets are unblocked.

Claims

1. A method comprising:

detecting a membership change at a port channel;

blocking fibre channel packets associated with the port channel at a first fibre channel switch upon detecting the membership change, the port channel including a plurality of links connecting the first fibre channel switch to a second fibre channel switch;

transmitting a plurality of flush packets on the plurality of links;

unblocking fibre channel packets associated with the port channel upon receiving acknowledgments for the plurality of flush packets from the second fibre channel switch.

2. The method of claim 1, wherein the membership change at the port channel comprises the addition or removal of a link.

3. The method of claim 1, wherein blocking fibre channel packets associated with the port channel comprises withholding credits from one or more input links providing the fibre channel packets.

4. The method of claim 3, wherein the packets are associated with a flow between a source and a destination.

5. The method of claim 4, wherein credits are withheld from links providing packets associated with the flow.

6. The method of claim 1, wherein the first switch includes a plurality of virtual output queues.

7. The method of claim 6, wherein virtual output queues associated with the port channel are blocked.

8. The method of claim 1, wherein unblocking fibre channel packets associated with the port channel comprises providing credits to one or more input links providing the fibre channel packets to the first fibre channel switch.

9. The method of claim 1, wherein the second switch flushes the packets associated with the plurality of links upon receiving the plurality of flush packets.

10. The method of claim 2, wherein flushing the packets comprises transmitting the packets at the second fibre channel switch.

11. A fibre channel switch comprising:

a processor configured to detect a membership change at a port channel and block fibre channel packets associated with the port channel upon detecting the membership change, the port channel including a plurality of links connected to a neighboring fibre channel switch;

an output interface configured to transmit a plurality of flush packets on the plurality of links;

wherein the processor is further configured to unblock fibre channel packets associated with the port channel upon receiving acknowledgments for the plurality of flush packets from the neighboring fibre channel switch.

12. The fibre channel switch of claim 11, wherein the membership change at the port channel comprises the addition or removal of a link.

13. The fibre channel switch of claim 11, wherein blocking fibre channel packets associated with the port channel comprises withholding credits from one or more input links providing the fibre channel packets.

14. The fibre channel switch of claim 13, wherein the packets are associated with a flow between a source and a destination.

15. The fibre channel switch of claim 14, wherein credits are withheld from links providing packets associated with the flow.

16. The fibre channel switch of claim 11, wherein the fibre channel switch includes a plurality of virtual output queues.

17. The fibre channel switch of claim 16, wherein virtual output queues associated with the port channel are blocked.

18. The fibre channel switch of claim 11, wherein unblocking fibre channel packets associated with the port channel comprises providing credits to one or more input links providing the fibre channel packets to the fibre channel switch.

19. The fibre channel switch of claim 11, wherein the neighboring switch flushes the packets associated with the plurality of links upon receiving the plurality of flush packets.

20. The fibre channel switch of claim 12, wherein flushing the packets comprises transmitting the packets at the neighboring fibre channel switch.

21. A system comprising:

means for detecting a membership change at a port channel;

means for blocking fibre channel packets associated with the port channel at a first fibre channel switch upon detecting the membership change, the port channel including a plurality of links connecting the first fibre channel switch to a second fibre channel switch;

means for transmitting a plurality of flush packets on the plurality of links;

means for unblocking fibre channel packets associated with the port channel upon receiving acknowledgments for the plurality of flush packets from the second fibre channel switch.

22. The system of claim 21, wherein the membership change at the port channel comprises the addition or removal of a link.

23. The system of claim 21, wherein blocking fibre channel packets associated with the port channel comprises withholding credits from one or more input links providing the fibre channel packets.

24. The system of claim 23, wherein the packets are associated with a flow between a source and a destination.

25. The system of claim 24, wherein credits are withheld from links providing packets associated with the flow.